The present invention relates to automotive fuel delivery systems and, in particular, to an improved locking ring for locking a fuel sender assembly to a fuel tank.
Conventional automotive fuel sending systems typically include a locking ring for securely mounting and sealing a fuel sender assembly to a fuel tank. Commonly, the locking ring is provided with lug supports along its outer peripheral edge which lockingly engage retaining lugs extending from the fuel tank for sealing the fuel sender assembly therebetween. Such systems are designed to permit a predetermined amount of fuel leakage and venting of fumes immediately upon impact to relieve any excessive pressure build-up within the fuel tank. However, it is critical that the fluid-tight seal between the fuel sender assembly and the fuel tank be maintained following venting of a pressure build-up to prevent excessive fuel and vapor leakage. In particular, a primary reason for premature release of fuel and fumes upon vehicular impact is the failure of the locking ring to withstand the increased tank pressure. The increased tank pressure acting on the fuel sender assembly and locking ring can cause permanent deformation of the retaining lugs. Structural deformation of the retaining lugs results in degradation of the seal between the fuel sender assembly and the fuel tank. Furthermore, with the advent of stricter vehicle safety standards, conventional fuel delivery systems are inadequate to meet minimum crashworthiness requirements.
It is therefore an object of the present invention to provide a relatively simple and inexpensive design for an improved locking ring for use in automotive fuel delivery systems. The improved locking ring of our invention can withstand substantially greater fuel tank pressures following vehicular impact than heretofore known rings. It is, therefore, very effective in inhibiting premature leakage of fuel and vapors from the fuel tank. The improved locking ring inhibits permanent deformation of the fuel tank retaining lugs to maintain the fuel sender assembly in a sealed relationship with the fuel tank.
One embodiment of the invention is directed to a fuel tank assembly comprising a hollow, pressurable tank for storing liquid fuel and having an aperture extending through a generally planar, external surface of the tank. The assembly also comprises a fuel sender unit, at least partially disposed within the aperture and having a radially-extending shoulder having generally parallel planar first and second surfaces. The second surface is adopted to be in a mating contact with the planar external surface of the tank, so as to enclose the aperture. A sealing means is placed between the second surface of the fuel sender unit and the planar, external surface of the tank for producing a fluid-tight seal therebetween. A plurality of retaining lugs extend from the planar, external surface of the tank. The retaining lugs comprise a first leg member extending substantially perpendicularly from the planar, external surface of the tank, and a second leg member, which is continuous with and extends generally orthogonally from one end of the first leg. The retaining lugs are located around the periphery of the aperture and radially outward of the shoulder of the fuel sender unit.
The assembly additionally comprises a locking ring, which comprises an engaging means for lockingly engaging the second leg member. The engaging means is adapted to coact with the second leg member to bias the shoulder of the fuel sender unit against the external tank surface. The engaging means is also adapted to bias the sealing means at a position radially inward of the first surface of the first leg, so as to lock the fuel sender unit to the tank. The locking ring further comprises one or more tabs for surrounding the second surface of the first leg. The tabs inhibit permanent radially outward deformation of the retaining lugs if pressure within the fuel tank is increased, for example, in a car accident. At least one upwardly projecting protrusion is placed in a surface of the locking ring. The protrusions, which extend in a radial direction of said locking ring, enhance the structural integrity of the locking ring, and therefore enable the fuel assembly to withstand higher pressures within the fuel tank than otherwise possible.
In one embodiment, the tabs comprise an inner flange and an outer flange. The inner flange comprises an upstanding projection which is capable of being lockingly engaged by the second leg member to lock the locking ring to the fuel tank.
Other advantages and features of the invention will become apparent from the following specification taken in connection with the accompanying drawings.